As was recently described in articles such as, "Silicon Quantum Wire Array Fabrication by Electrochemical and Chemical Dissolution of Wafers," L. T. Canham, Appl. Phy. Lett., V. 57. pg. 1046 (1990) and "Resonant Tunneling v a Microcrystalline-Silicon Quantum Confinement," Q. Ye et al, Phys. Rev. B44, pg. 1806 (1991), porous silicon as well as nanometer scale clusters of other semi-conducting materials exhibit bright photoluminescence at room temperature and resonant tunneling and coulomb blockade effects in the electrical transport. In these articles, it is theorized that these materials exhibit these qualities because they have discrete electronic energy spectrums in contrast to the continuous energy bands exhibited by bulk samples of the same materials. Therefore, quantum confined microclusters and/or microparticles of silicon and other semiconducting materials offer the possibility for novel high performance electronic devices which are compatible with established silicon based technologies.
In the above cited articles, the silicon microclusters were formed by two distinct fabrication techniques. These techniques may be briefly described as electrochemically etching silicon wafers to form porous silicon and as recrystallizing silicon microparticle films. Both of these techniques, however, involve chemical processes that are not easily controlled and only produce microparticles of silicon which are embedded in bulk material.
Other gas phase chemical processes for producing independent silicon microparticles have been reported in such articles as, "Above-band-gap photoluminescence from Si fine particles with oxide shell," H. Morisak et al, J. Appl. Phys., 70, pg. 1869 (1991). However, the photoluminescence generated from microparticles produced using this reported method has been very weak as compared with the photoluminescence from porous silicon.